Andrew Tillett, Sara Wiggins & Inspector Wyatt Book Three

Young Andrew Tillett liked retired Sergeant Major Polk when their mutual friend, Inspector Peter Wyatt of Scotland Yard, introduced them. The three went into a pub to talk after an unexpected meeting on the street: but there, though Polk and Wyatt had known each other for years, Polk seemed nervous, and interrupted their conversation to speak with a heavy-set scar-faced man. The two almost came to blows, yet Polk refused to reveal much of what the encounter meant.
A few days later Polk was dead. He had been working for Lord Somerville, at a villa not far from Andrew's home, and had been murdered, Lord Somerville said, as he was getting the household coach ready for a journey. Robbery seemed to be the motive, because a chest of valuable archeological treasures had been stolen. Lord Somerville had conducted a number of digs in Mesopotamia.
Because Andrew had liked Polk, and because he and his friend Sara were always intrigued by a mystery, they made it their business to find out as much about what was going on as possible. Especially after Wyatt was assigned to the case.
What did the scar-faced man have to do with the murder? Were a mysterious chimney sweep and his French apprentice involved in any way? And were Somerville and his housekeeper, who were the only ones about at the time of the crime, telling all they knew? Or was Lord Somerville keeping a secret that was somehow a part of this?
Once again, as in The Case of the Baker Street Irregular and The Case of the Vanishing Corpse, Robert Newman spins a web of story that builds mystery on mystery and suspense on suspense.